Ignition system



June 25, 1946. w. w. EITEL 2,402,539

' v IGNITION SYSTEM Filed Oct. 11, 1943 23 Y2, (I x En \M Z! /9 ri s f;2

HIS ATTORNEY Patented June 2 5, 1946 IGNITION SYSTEM William W. Eitel,San Bruno, Califi, assignor to Eitel-McCullough, Inc., San Bruno, CaliL,a

corporation of California Application October 11, 1943, Serial to.505,885

Claims. (01. 123148) My invention relates to an ignition system for aninternal combustion engine.

The broad object of my invention is to pro-' vide an improved ignitionsystem embodying resonant means located in the combustion chamber andenergized by a high frequency 05- cillator to produce a discharge. I

The invention possesses other objects and features of advantage, some ofwhich, with the foregoing, will be set forth in the followingdescription of my invention. It is to be understood that,

I do not limit myself to this disclosure of species of my invention, asI may adopt variant embodiments thereof within the scope of the claims.

Referring to the drawing:

Figure 1 is a diagrammaticview of an ignition system embodying theimprovements of my invention; and

Figure 2 is a detail sectional view showing the portion of the enginecylinder containing the resonant means.

conditions a discharge can be made to occur across the gap, at the openend of the line.

Oscillator 8 may be of any suitable'typeadapted to produce oscillationsat the desired frequency. That shown comprises a pair 0f tri0des I!connected in a circuit having a tank coil I! from which energy istransferred by a coil l3 feeding into a transmission line M. The lattermay be of any suitable type such as a concentric line comprising 'anouter tubular conductor l6 and an inner conductor l1. As shown in Figure2, tube i6 is threaded into an aperture extending through the side wallof the combustion cham-" her and is plug ed by a suitable insulator 18through which inner conductor l1 projects. Conductor I1 is connected tothe resonant line adjacent its shorted end.

Means are provided for keying the oscillator with pulses timed with theoperation of the enw gine. This is done by discharging condenser l9Figure 3 is a sectional view similar to Figure 2, showing a modifiedarrangement.

Figure 44s a detail sectional view of an engine cylinder, disclosinganother modified construction.

In terms of broad inclusion, my ignition system for an engine comprisesresonant means in the combustion chamber adapted when energized toproduce a discharge, a high frequency oscillator, means transferringenergy from the oscillator to the resonant means, and means keying theoscillator to energize the resonant means in time with the operation ofthe engine.

In greater detail, and referring to Figures 1 and 2 of the drawing, myignition system is shown more or less diagrammatically in conjunctionwith an engine having acyllnder l andassociat-- ed piston 2. Thecylinder (has suitable intake and exhaust valves 3 ported intocombustion chamber 5, and piston 2 i connected by a rod 8 to a crankshaft I.

-Resonant means are provided in the combustion chamber for producing adischarge when energized by a suitable oscillator 8. The typeof resonantmeans shown in Figures 1 and 2 comprises a quarter-wave line made up oftwo parallel metallic rods 9 secured at one end to the cylline of thiskind, when properly. energized, .willinto the oscillator, the dischargesbeing timed by a suitable switching device such as rotatable contactor2| interposed in lead from the condenser to the oscillator. Contactor 2|is rotated 36 by a suitable drive means (indicated by dot and have apotential node atthe shorted end and a Y potential antinode at the openend. tinder these transmission line is employed comprising two parallelwires or rods 2d projecting into the combustion chamber through asuitable insulator 2s mounted on a, threaded plug 21. The line sectionprojecting into the combustion chamber is substantially ,dwave inlength, thus placing the potential node at the chamber wall. This beinga tuned line it is understood that the line portions external thecylinder should b some multiple of a quarter-wave. Since the timed lineenters the combustion chamber at a potential node the insulationproblems at this point are reduced to a minimum.

Figure 4 shows another modification in which the combustion chamber isshaped to form a, resonant cavity having a gap 28 therein adapted toprovide a. discharge'when the cavity is'energized. Energy is transferredfrom the oscillator by a. coninto the resonant cavity.

' I claim:

centric line terminating in'a loop 23 projecting 1. An ignition systemfor an engine having a combustion chamber, comprising resonant means inthe chamber adapted when energized to produce a discharge, a, highfrequency oscillator,

means transferring-energy from the oscillator to said resonant means,and means keying the oscillator to energize the resonant means in timewith the operation of said engine.

2. An ignition system for an engine having a combustion chamber, aresonant cavity formed means transferring energy from the oscillator tosaid line, and means keying the oscillator to energize the line in timewith the operation of said engine.

4. An ignition system for an engine having a combustion chamber, aresonant line projecting into the chamber. adapted when energized toproduce a discharge, a high frequency oscillator, means transferringenergy from the oscillator to said line, and means keying the oscillatorto energize the line in time with the operation of said engine, thelength of the line in said chamber being such as to place a potentialnode adjacent a wall of the chamber.

5. An ignition system for. an engine having a combustion chamber, aresonant. line projecting into the chamber adapted when energized toproduce a discharge, a high frequency oscillator, means transferringenergy from the oscillator to said line, and means keying the oscillatorto en,- ergize the line in time with the operation of said engine, thelength of the line in said chamber being substantially one-quarter wavelength at the frequency of said oscillator,

, 'WILLIAM W. EITEL.

